Scientists using an extract of whole-plant marijuana rich in pot's main psychoactive ingredient THC as well as cannabidiol (CBD) showed "dramatic reductions in tumor volumes" of a type of brain cancer.

"High-grade glioma is one of the most aggressive cancers in adult humans and long-term survival rates are very low as standard treatments for glioma remain largely unsuccessful," according to researchers Katherine A. Scott, Angus G. Dalgleish, and Wai M. Liu from the Oncology Department at St. George's University of London.